The present invention relates to a process for riveting with a blind rivet, and to corresponding blind rivets.
Blind rivets are generally comprised by a tubular sleeve with a longitudinal bore, and a mandrel comprising, for one part, a head of the mandrel having a diameter greater than that of the bore of the sleeve, and for the other part, a shank housed in the bore of the sleeve and extending therefrom at the end of the sleeve opposite to the head of the mandrel. Such rivets are adapted after pulling on the shank of the mandrel to form a head of the blind rivet, by introducing the head of the mandrel into the end adjacent the sleeve, and for maintaining the materials together between a preformed head of the sleeve and the blind head.
The shank of the mandrel is adapted to be broken upon completion of the riveting, in order that it not extend from the sleeve.
These rivets are called "blind" because they are introduced and set it place in the pieces to be assembled, from just one side of the assembly. Such placement is necessary when one of the sides of an assembly is not accessible.
Once set, the blind rivet subjects the assembly of materials to compressive forces of a known type.
However, after stopping application of the forces necessary for setting the rivet, the effect of compression on the assembly has a tendency to be relaxed by a hysteresis effect, such that an axial relaxation leading to a disadvantageous loosening is produced. The sleeve and the assembly then have created between them a certain play, which is harmful to good securing of the assemblage, and creates a poor fastening of the different elements between themselves.
The present invention has as its object to overcome all of these drawbacks by providing a riveting process by means of blind rivets, resulting from a correct fastening, and having no tendency to be relaxed, and not creating disadvantageous play between the different elements being assembled.
The invention provides also for the provision of rivets enabling carrying out such a process.